Preparation of oil solutions of basic alkaline earth metal petroleum sulfonates



March 1956 H. w. ANDERSON ET AL 2,738,326

PREPARATION OF OIL SOLUTIONS OF BASIC ALKALINE EARTH METAL PETROLEUM SULFONATES Filed Oct. 4, 1952 TBA Oil Sdurion a? basic Calcium Pz'i'r-deum $ulona+es Ham-L Wagne Anderson Gran? Edward Warren Richard Ne barTholoL-new L) (Hi-orig:

United States Patent PREPARATION OF OIL SOLUTIONS OF BASIC .gLll gigLllgE EARTH METAL PETROLEUM SUL- Henry Wayne Anderson and Grant Edward Warren, Martinez, and Richard Neil Bartholomew, Richmond, Calif., assignors to Shell Development Company, Emeryville, Calif., a corporation of Delaware Application October 4, 1952, Serial No. 313,142

a 3 Claims. (Cl. 252-33) 'This invention relates to the preparation of organic sulfonic acids, their sulfonatesand thevarious derivatives thereof, and particularly to petroleum sulfonic acids, and their derivative salts, which petroleum sulfonic acids may be prepared by the treatment of petroleum oils with a sulfonating agent. The invention is concerned more particularly with the preparation of oil-soluble petroleum sulfonic acids and their sulfonates, often designated mahogany sulfonic acids and sulfonates, especially the oil-soluble alkaline earth metal sulfonates.

It is well known to acid-treat various hydrocarbon oils with strong sulfuric acid for the purpose of improving certain qualities of the oil by removing substances therefrom which impart undesirable properties to the oil. Various reaction products are formed in this treatment, including sulfonic acids, some of which are oil-soluble and some oil-insoluble or water-soluble, the relative amounts depending upon factors such as the nature of the oil, the severity of acid-treatment, and the like. It is also well known to recover these sulfonic acids by various methods, as incidental to the purification of the oil. Various methods are also practiced where the principal purpose is to produce either oil-soluble sulfonic (mahogany) acids or water-soluble sulfonic (green) acids, or both. Salts of the former have been found to be of increasing value in hydrocarbon oil compositions, such as lubricating composition, andsalts of the latter are particularly valuable in the formulation of insecticidal spray compositions. Furthermore, various methods are also practiced where the principal purpose is to produce oilsoluble petroleum sulfonates, such as oil-soluble alkaline earth metal petroleum sulfonates, especially the highly basic derivatives thereof.

In the preparation of oil-soluble alkaline earth metal petroleum sulfonates, for example, calcium mahogany sulfonates, and basic derivatives thereof, suchas a material which may be considered to be equivalent to monohydroxy calcium sulfonate and which may be represented by the generalized formula RSOsCaOH, wherein R represents a hydrocarbyl radical, such as from a petroleum lubricating oil stock, it has been the practice to treat a suitable oil stock, such as a lubricating oil distillate fraction, with a suitable sulfonating agent, such as concentrated (90100% H2804) or fuming (greater than 100% H2804) sulfuric acid or chlorosulphonic acid or a sulfonating mixture of sulfur dioxide and sulfur trioxide, at normal atmospheric or slightly elevated temperatures, and with agitation, until satisfactory reaction takes place. The reaction mixture is permitted to stand in a quiescent state so that the formed sludge, generally containing resinous material, excess acid and oilinsoluble (green) sulfonic acids, may separate as a lower layer from the upper layer containing oil and oilsoluble (mahogany) sulfonic acids dissolved therein. After separation of the two layers, the oil layer containing the oil-soluble sulfonic acids (molecular weight from about 300 to about 600, preferably from 400 to 525) is treated with a basic-acting alkali metal compound such ice as NaOH, KOH, LiOH, NazO, NazCOs, etc., either as a solid or in an aqueous solution (e. g., an aqueous sodium hydroxide solution) to neutralize the acids therein, especially the oil-soluble sulfonic acids and to convert these oil-soluble sulfonic acids to the corresponding oil-soluble alkali metal sulfonates. Any mineral acid or acid anhydride (such as may originate from the sulfonating agent employed) present in the oil layer, either dissolved or entrained therein, is also neutralized to yield its corresponding alkali metal salt.

After contacting the oil layer with an aqueous sodium hydroxide solution, the mixture is allowed to settle, yielding an oil layer containing the oil-soluble sodium sulfonates and a water layer containing some dissolved salts and entrained oil.

The oil layer containing the sodium mahogany sulfonates is then extracted with an oxygenated organic liquid, such as an alcohol, to obtain a more concentrated, relatively inorganic salt-free, oil solution of sodium sulfonates. Since a highly basic calcium petroleum sulfonate is not stable in the presence of the oxygenated organic solvent, it is necessary to remove the solvent, as by distillation, prior to the conversion step. Readdition of oil is also generally required to obtain suitable sulfonate concentration for the conversion.

The oil concentrate is then contacted at an elevated temperature, usually in the neighborhood of 180200 F. for a substantial length of time, simultaneously with a molar excess of CaClz as required by Equation 1 below:

(1 2RSO3Na+CaCl2- Ca (RSOs z+2NaCl (neutral calcium sulfonate) (2) Ca(RSO3)z+Ca(Ol-I)2 2RSO3CaOH (monohydroxy calcium sulfonate) and plus a substantial amount from about 5 to about 50% by weight of water, based on the oil and sodium sulfonates. The reaction mixture is then permitted to settle to form an oil phase containing dissolved basic calcium sulfonate, which for purposes of simplicity may be represented as substantially equivalent to monohydroxy calcium sulfonate, and a water phase containing some dissolved inorganic salts. Although the basic calcium sulfonate derivative is described as substantially equivalent to monohydroxy calcium sulfonate, in general, the per cent basicity is less than 50%, usually between about 40% and about 20%. Per cent basicity is defined accord- .ing to the following relationship:

Usually the basic calcium sulfonate derivative may be considered as equivalent to (RSO3)2Ca plus RSOsCaOH or (RSOs)2Ca plus Ca(0H)z, or a mixture of all these three materials.

The oil layer, after separation from the Water layer, is dehydrated and then filtered to remove any suspended solids.

The above process has been carried out as a batch process. It is unsuitable for modification or adaptation to a continuous basis because of (a) the relatively high viscosity of the sodium sulfonate concentrate, (b) techni cal problems in handling concentrated lime-calcium chloride slurries, and (c) the length of time required for phase separation due to emulsion difiiculties. Moreover, the product obtained is limited to moderate ash levels, about 8.5% w. sulfated ash content, by the adverse effect of viscosity on settling rates. The commercially acceptable limit for shipment and handling of the finished product is about w. sulfated ash.

It is, therefore, a principal object of the present invention to provide an improved process for the preparation of oil-soluble alkaline earth metal petroleum sulfonates. Another object is to provide an improved process for the preparation of highly basic, oil-soluble, alkaline earth metal petroleum sulfonates of relatively high sulfated ash content. A more specific object is to provide a continuous process for the preparation of oil-soluble basic alkaline earth metal, particularly calcium, petroleum sulfonates from oil-soluble alkali metal, particularly sodium, petroleum sulfonates obtained in the sulfonation of mineral oils. Other objects and advantages will become apparent from the following description made with reference to the accompanying drawing which is a schematic flow diagram which represents a continuous process for the preparation of oil-soluble basic alkaline earth metal petroleum sulfonates.

According to the present invention, it has been found that an oil solution of highly basic alkaline earth metal petroleum sulfonates can be continuously prepared from an oil solution of petroleum sulfonates, containing a monovalent, inorganic alkaline cation, such as the alkali metal and ammonium petroleum sulfonates, by a process comprising contacting the oil solution of the monovalent cation petroleum sulfonates, in solution in a substantial proportion of a low molecular weight, substantially watersoluble and oil-soluble oxygen-containing organic liquid, with an amount of a water-soluble inorganic alkaline earth metal salt to convert a substantial proportion of the monovalent cation petroleum sulfonates to neutral alkaline earth metal petroleum sulfonates, and with suificient water to cause the formation of a phase comprising said oxygen-containing organic liquid containing an oil solution of the neutral alkaline earth metal sulfonates dissolved therein, and an aqueous phase; separating the phases thus formed; adding to the oxygen-containing organic liquid phase a substantial amount of a basic compound of the corresponding alkaline earth metal, and a substantial amount of water; and removing from the resulting mixture the oxygen-containing organic liquid, whereby an oil solution of basic alkaline earth metal petroleum sulfonates is obtained.

Described more specifically, the process of the present invention comprises continuously contacting an elevated temperature, e. g., at a temperature of from about room temperature to about 170 F., and preferably from about 110 F. to about 130 R, an oil concentrate of alkali metal, particularly sodium, or ammonium. petroleum sulfonates, in solution in a low molecular weight, substantially oil-soluble alkanol or alkanone, the solution containing from about to about 50%, preferably from about to about by weight of the oil concentrate, with at least 1 molar quivalent, and preferably from about 1.5 to about 2 molar equivalents, of a water-soluble, inorganic alkaline earth metal salt, such as calcium chloride, according to Equation 1 shown above, to convert a substantial proportion of the alkali metal or ammonium petroleum sulfonates to neutral alkaline earth metal petroleum sulfonates, and with sufficient water to cause the formation of an aqueous phase containing dissolved and/or suspended inorganic salts and minor amounts of the alkanol or alkanone solvent, and a phase comprising an oil solution of neutral alkaline earth petroleum sulfonates dissolved in the alkanol or alkanone solvent; continuously separating the resulting phases; continuously adding to the neutral alkaline earth metal petroleum sulfonates-containing phase from about 0.75 to about 1.5 molar equivalents of an alkaline earth metal oxide or hydroxide, according to Equation 2 shown above and based on the sodium sulfonates in the original mixture, and a substantial amount of water; and continuously removing from the resulting mixture the alkanol or alkanone solvent, whereby an oil solution of basic alkaline earth metal petroleum sulfonates is obtained. The resulting oil solution is then dehydrated and filtered to remove suspended solids.

The low molecular weight oxygen-containing liquid is preferably one which is substantially soluble mineral oil and chemically non-reactive therewith at operating temperatures. The C4- to Cs-alkanols and alkanoncs are preferred for the practice of the invention, the monohydroxy and monoketo-componnds being understood. The C4- and cs-alkanols, and the cl-alkanones, being substantially soluble in water as well as in mineral oil, are preferred. The organic solvent is best represented by tertiary butyl alcohol, tertiary amyl alcohol, and methyl ethyl ketone. The organic solvent not only lowers the viscosity of the sulfonate solutions but also prevents the formation of stable emulsions.

it is generally necessary to dilute the neutral alkaline earth metal petroleum sulfonate solution with an amount of a hydrocarbon oil which will give a resulting oil solution of basic alkaline earth metal petroleum having a sulfated ash content of from about 9% w. to about 11% w. The viscosity of an oil solution of basic alkaline earth metal petroleum sulfonates increases very rapidly above 8% W. sulfated ash, and sulfated ash contents of above from about 10% W. to about 12% w. are not commercially feasible. The diluent oil should be added before dehydration and filtration, and preferably before the removal of the organic liquid. The diluent is preferably a refined lubricating oil of lowest practical viscosity compatible with other characteristics, such as flash point, oxidation stability, etc., determined by the final product in which the sulfonates are to be used.

The presence of water is necessary to incorporate alkalinity in the oil solution of neutral alkaline earth metal petroleum sulfonates. It has been found that practically no alkaline earth metal base enters the oil phase with less than about 2% by weight of water present. Sufficient water should be present in the reaction mixture so that from about 4% to about 8% by weight remains in the residue after substantial removal of the oxygencontaining organic liquid. It is believed that basification actually occurs during the removal of the organic liquid and/or during subsequent drying.

Since basification does not occur until during or after removal of the oxygen-containing organic liquid, the alkaline earth metal oxide or hydroxide can be added to the oil solution of neutral alkaline earth metal petroleum sulfonates after removal of the oxygen-containing organic liquid therefrom. It is preferred, however, to add the alkaline earth metal base prior to removal of the oxygencontaining organic liquid, since the alkaline earth metal base also lowers the viscosity of the oil solution of neutral alkaline earth metal petroleum sulfonates.

The petroleum hydrocarbon material which can be sulfonated to produce the oil-soluble basic calcium sulfonate according to this invention includes the various petroleum hydrocarbon oils and distillate fractions thereof, particularly those which possess lubricating properties, and which are of the mixed type, i. e., containing naphthenic type hydrocarbons. In general, it is preferred to use hydro carbon oil fractions derived from naphtheuic Gulf Coastal, Mid-Continent or California crudes, particularly the lubricating oil fractions obtained from such crudes. Prior to sulfonation the oil can be, and preferably is, solvent treated, as with sulfur dioxide, furfural, or various other well known selective solvent treating agents.

A naphthenic oil which is particularly useful for the production of the oil-soluble sulfonic acids and the basic alkaline earth metal sulfonates is a furfural or an Edeleanu ratfinate of a naphthenic oil distillate having the following properties:

Viscosity, SSU at F 400-900 Viscosity index 30-60 Gravity, API 20-30 Refractive index N 1.47-1.52 Flash (C. O. 0), F 350-450 Representative of suitable oil stocks are the 15-20 V. I. up to about 33 V. I. and 55 V. I. rafiinates, such as can be obtained by solvent extractioi of 60 SSU at 210 F. distillates derived from an 80/20 Poso/Coalinga, California crude mixture.

Sulfonation of the petroleum hydrocarbon material j with subsequent neutralization of the free acids with an alkali metal hydroxide, can be eifected by known methods, such as the Water Dilution Sulfonation Process described in detail in U. 5. Patent No. 2,578,657, issued December 18, 1951, or by the Hydrocarbon Dilution Process described hereinafter.

The crude oil solution of alkali metal (e. g., sodium) petroleum sulfonates obtained by either of the abovementioned methods, contains minor amounts of inorganic salts. For the purposes of the present invention, it is desirable to remove substantially all of the inorganic salts as well as a portion of the unsulfonated oil. Extraction, concentration, and purification of the oil-soluble sodium petroleum sulfonates can be eiiected by contacting the crude oil solution with a minor amount of water and with a minor proportion of a low molecular weight oxygencontaining organic liquid which is at the same time substantially soluble both in water and in the mineral lubricating oil, under conditions of temperature, pressure, and relative proportion selected to yield, upon Stratification, three distinct liquid phases, an oil-rich phase, ar organic solvent-rich phase, and a water-rich phase, separating the solvent-rich phase from the other phases, and recovering a concentrated and purified oil-soluble sulfonate from the solvent-rich phase. When utilizing the concentrated and purified oil-soluble sodium petroleum sulfonates as the starting material in the conversion process of the present invention, obviously, it is most advantageous to use, as

the oxygen-containing solvent in the concentration and purification operation, an oxygen-containing solvent which is also suitable for the conversion process. The solventrich phase from the concentration operation can then be used directly as the starting material in the present invention. Tertiary butyl alcohol is preferred as the solvent in both operations.

A preferred embodiment of the invention will now be described in detail with reference to the accompanying drawing which is a schematic flow diagram representing a preferred embodiment of the present invention. The material to be sulfonated to obtain the oil solution of sodium petroleum sulfonates is a 30 V. I. furfural-raflinate of a bulk distillate having a viscosity of 60 SSU at 210 F obtained from a mixture of naphthenic and mixed base California cnldes. The raifinate contains about 65% paralfins and naphthenes, about 20% monocyclic aromatics, about 13% dicyclic aromatics, and about 2% of resins and polycyclic aromatics, all percentages being by weight. The oil is given a pretreatment with about by weight of 98% sulfuric acid to remove a portion of the more reactive and undesirable highly aromatic materials. The pretreat-sludge is separated by stratification, about 7.2% of the oil feed being lost. The pretreated oil is then sulfonated with about 35% by weight of oleum (105.5% H2804), the mixture being cooled to maintain the temperature at about 110 F, the reaction being highly exothermic. The sulfonation mixture is countercurrently blown with air to remove sulfur dioxide and the air-blown sulfonation mixture is then intimately mixed with about 2 volumes of an essentially paraffinic/naphthenic naphtha solvent (190-220 F. boiling range) and the mixture allowed to stratify. The heavy acid tarry sludge is then separated from the naphtha-oil solution of oil-soluble petroleum sulfonic acids. Considering the organic content of the sludge derived from the oil as sulfonic acids, the approximate ratio of sulfonic acids in the sludge to the 'sulfonic acids in the separated naphtha-oil phase is 9-10. The naphtha-oil-mahogany acid solution is then neutralized with a slight excess (10%) of about aqueous caustic alkali. The neutralized mixture is then 6 allowed to stratify; about 4% of the total separates as an aqueous phase which contains a moderate concentration of inorganic salt. The naphtha-oil-sodium mahoganate (oil-soluble petroleum sulfonate) solution is heated to about 260 F., the major proportion of the naphtha solvent flashed off, and the remainder of the solvent steamstripped at about 240-260 F. The resulting crude oil solution of sodium petroleum sulfonates has the approximate weight'composition: Oil-76.5%; RSO2Na19.5%; water2.5%; inorganic salts1.5%, all percentages being by weight. Since a light hydrocarbon naphtha is used in this sulfonation process to dilute the sulfonation reaction mixture, the process is identified as the Hydrocarbon-Dilution Process and the sulfonates as Hydrocarbon-Dilution sulfonates. The crude sulfonate solution is then contacted with water and tertiary butyl alcohol, the water: crude sulfonate weight ratio being about 0.3 and the alcohol: crude sulfonate weight ratio being about 0.6. The resulting mixture is permitted to settle to obtain three phases: an oil-rich phase, a water-rich phase, and a TBA-rich phase, and the resulting phases are separated. The TBA extract has the approximate weight composition: Sodium sulfonates-17.5 oil-41.3%; TBA51.0%; water-20.0%; inorganic salts0.2%.

Now, referring to the drawing, the TBA extract is continuously introduced into a suitable mixing-settling device 1 by means of line 2 and passed therefrom by means of line 4 to a second mixing settling device 5, countercurrently to an aqueous solution of an inorganic calcium salt, preferably calcium chloride, which is continuously introduced by means of line 6 into mixer-settler 5 and passed therefrom by means of line 7 to mixer-settler 1.

The aqueous solution contains from about 1.5 to about 2.0 molar equivalents of the calcium salt, according to Equation 1 shown above and based on the sodium sulfonate content of the TBA extract. The concentration of the calcium salt solution is from about 5% to about 60%, and preferably from about 20% to about 30% by weight. The temperature of reaction and settling is maintained at from about 110 F. to about 130 F., preferably at about 120 F. At least about of the sodium petroleum sulfonates are converted to neutral calcium petroleum sulfonates. Although a two-stage countercurrent contacting system is shown, it is to be understood that any number of stages can be used.

The resulting aqueous phase, containing inorganic salts, traces of water-soluble sulfonates, and a minor amount of TBA, was continuously withdrawn from mixer-settler 1 by means of line 9, and was passed to an alcohol recovery unit, not shown. The resulting alcoholic phase containing an oil solution of neutral calcium sulfonates was continuously withdrawn from mixer-settler 5 by means of line 10. To this alcoholic phase was continuously added a lime slurry, introduced by means of line 11 and containing from about 0.75 to about 1.5 molar equivalents of calcium hydroxide, according to Equation 2 above, and based upon the sodium sulfonate content of the TBA extract, and a diluent hydrocarbon oil, introduced by means of line 12. The concentration of the lime slurry is from about 10% to about 40%, and preferably from about 20% to about 30% by weight. The diluent oil is added in an amount sufiicient to reduce the sulfated ash content of the resulting oil solution of basic calcium sulfonates to from about 9% w. to about 11% w. The diluent oil is preferably a hydrocarbon oil having a viscosity of from about 90 to about 110, preferably about 100, SSU at F.

The resulting mixture is then passed through a suitable heating device 14 where it is heated to a temperature of about 220-250 F. The heated mixture is introduced by means of line 15 into a suitable flash and dehydration column 16 where it is flashed at a temperature of about 220-250 F. at atmospheric pressure to remove the TBA and a substantial proportion of the water present, and where it is also dehydrated at a tempera- 7 ture of about 290310 F. to remove the remaining water. The two-step flashing and dehydration operation can be accomplished in a single column as shown, or in two separate columns. The resulting oil solution of basic calcium petroleum sulfonates is removed from flash and dehydration column 16 by means of line 17 and is passed to a suitable filtering device 19, such as a rotary filter, to remove suspended solids. The finished solution of basic calcium petroleum sulfonates in oil is removed by means of line 20.

The following example illustrates the process of the invention:

A TBA extract of an oil solution of sodium petroleum sulfonates was contacted, in a two-stage countercurrent flow system at a temperature of about 120 F, with 1.75 molar equivalents of calcium chloride per equivalent of sodium sulfonate, using a 20% calcium chloride solution. The resulting alcoholic phase containing an oil solution of neutral calcium sulfonates was separated from the resulting aqueous phase. A 25% W. lime slurry containing 1.5 molar equivalents of Ca(OI-I)z per equivalent of sodium sulfonate, and suflicient 100 HVI Neutral Oil to obtain an oil solution of basic calcium petroleum sulfonates of about W. sulfated ash content were then added to the alcoholic phase. The resulting mixture was flashed at a temperature of about 240 F., under atmospheric pressure, to remove the TBA, and was then dehydrated at a temperature of about 300 F. The resulting oil solution was then filtered to remove suspended solids. The finished oil solution of basic calcium petroleum sulfonates had a base no. (mg. KOH/ g. concentrate) of 25.15, a sulfated ash content of 10.4% w., and a control ratio of 2.42. The control ratio is expressed by Base no.

Per cent sulfated ash The per cent conversion of sodium sulfonates to neutral calcium sulfonates was 98.1%.

Although the invention has been described in detail with reference to the preparation of oil solutions of basic alkaline earth metal petroleum sulfonates from oil solutions of sodium petroleum sulfonates, it is to be understood that the invention is equally applicable to the preparation of oil solutions of basic calcium, barium, and strontium petroleum sulfonates from oil solutions of sodium, potassium, lithium, or ammonium petroleum sulfonates.

We claim as our invention:

1. The method of preparing an oil solution of oilsoluble basic calcium petroleum sulfonates which comprises continuously contacting a tertiary butyl alcohol solution containing from about 30% to about 40% by weight of an oil solution of oil-soluble sodium petroleum sulfonatcs with an aqueous solution containing from about to about 30% by weight of calcium chloride and containing from about 1.5 to about 2 molar equivalents of calcium chloride per equivalent of sodium sulfonate, whereby a tertiary butyl alcohol phase containing an oil solution of oil-soluble neutral calcium petroleum sulfonates, and an aqueous phase are formed; continuously separating the alcohol phase from the aqueous phase; continuously adding to said alcohol phase from about 0.75 to about 1.5 molar equivalents of calcium hydroxide per equivalent of sodium sulfonate, and a substantial amount of water, the amount of such added water being such that when the alcohol is removed from the mixture as is hereinafter provided, the resulting mixture contains from about 4 to about 8 per cent by weight of water; continuously removing said alcohol from the resulting mixture, and thereafter continuously removing the remaining water from the alcohol-free mixture, whereby an oil solution of oil-soluble basic calcium petroleum sulfonates is obtained.

2. The method of preparing an oil solution of oilsoluble basic calcium petroleum sulfonates which comprises contacting a tertiary butyl alcohol solution containing from about 20% to about 50% by weight of an oil solution of oil-soluble sodium petroleum sulfonates with an aqueous solution containing from about 10% to about 40% by weight of calcium chloride and containing from about 1.5 to about 2 molar equivalents of calcium chloride per equivalent of sodium sulfonate, whereby a tertiary butyl alcohol phase containing an oil solution of oil-soluble neutral calcium petroleum sulfonates, and an aqueous phase are formed; separating said alcohol phase from said aqueous phase; adding to said alcohol phase from about 0.75 to about 1.5 molar equivalents of calcium hydroxide per equivalent of sodium sulfonate, and a substantial amount of water, the amount of such added water being such that when the alcohol is removed from the mixture as is hereinafter provided, the resulting mixture contains from about 4 to about 8 per cent by weight of water; removing the alcohol from the resulting mixture, and thereafter continuously removing the remaining water from the alcohol-free mixture, whereby an oil solution of oil-soluble basic calcium petroleum sulfonates is obtained.

3. The method of preparing an oil solution of oilsoluble basic calcium petroleum sulfonates which comprises contacting a solution comprising from about 20% to about 50% by weight, based on the weight of the solution, of an oil solution of oil-soluble sodium petroleum sulfonates dissolved in an oxygen-containing organic liquid selected from the group consisting of C4- to C0- alkanols and alkanones, with an amount of a water-soluble inorganic salt of calcium sufiicient to convert a substantial proportion of the sodium petroleum sulfonates to neutral calcium petroleum sulfonates, and with sufficient water to cause the formation of a phase comprising said oxygen-containing organic liquid containing an oil solution of neutral calcium petroleum sulfonates dissolved therein, and an aqueous phase; separating the phases thus formed; adding to the oxygen-containing organic liquid phase a substantial amount of a basic compound of calcium, and a substantial amount of water, the amount of such added water being such that when the oxygen-containing liquid is removed from the mixture as is hereinafter provided, the resulting mixture contains at least about 2% by weight of water; removing from the resulting mixture said oxygen-containing organic liquid, and thereafter continuously removing the remaining water from the resulting mixture, whereby an oil solution of oil-soluble basic calcium petroleum sulfonates is formed.

4. The method of preparing an oil solution of oilsoluble basic alkaline earth metal petroleum sulfonates which comprises contacting a solution comprising from about 20% to about 50% by weight, based on the weight of the solution, of an oil solution of oil-soluble alkali metal petroleum sulfonates dissolved in an oxygen-containing organic liquid selected from the group consisting of Cito Cs-alkanols and alkanones, with an aqueous solution containing from about 10% to about 40% by weight of a water-soluble inorganic alkaline earth metal salt and containing from about 1.5 to about 2.0 molar equivalents of said inorganic alkaline earth metal salt per equivalent of alkali metal petroleum sulfonate, whereby a phase comprising said oxygen-containing organic liquid containing an oil solution of neutral alkaline earth metal petroleum sulfonates dissolved therein, and an aqueous phase are formed; separating the phases thus formed; adding to said oxygen-containing organic liquid phase from about 0.75 to about 1.5 molar equivalents of a basic compound of the corresponding alkaline earth metal per equivalent of alkali metal petroleum sulfonate, and a substantial amount of water, the amount of such added water being such that when the oxygen-containing liquid is removed from the mixture as is hereinafter provided, the resulting mixture contains from about 4 to about 8 per cent by weight of water; removing from the resulting mixture said oxygen-containing organic liquid, and thereafter continuously removing the remaining water from the resulting mixture, whereby an oil solution of oil soluble basic alkaline earth metal petroleum sulfonates is obtained.

5. The method according to claim 4, wherein said oxygen-containing organicliquid isa Ct-alkanol.

6. The method according to claim 4 wherein said oxygen-containing organic liquid is a C4-alkanone.

7. The method of preparing an oil solution of oilsoluble basic alkaline earth metal petroleum sulfonates which comprises contacting a solution comprising from about 20% to about 50% by weight, based on the weight of the solution, of an oil solution of oil-soluble petroleum sulfonates having a monovalent inorganic alkaline cation nates dissolved therein, and an aqueous phase; separating the phases thus formed; adding to the separated oxygencontaining organic liquid phase a substantial amount of a basic compound of the corresponding alkaline earth metal, and a substantial amount of water, the amount of such added water being such that when the oxygen-containing liquid is removed from the mixture as is hereinafter provided, the resulting mixture contains at least about 2% by weight of water; removing from the resulting mixture said oxygen-containing organic liquid and thereafter continuously removing the remaining water from the resulting mixture, whereby an oil solution of oilsoluble basic alkaline earth metal sulfonates is obtained.

8. The method of preparing an oil solution of oilsoluble basic alkaline earth petroleum sulfonates which comprises contacting a tertiary butyl alcohol solution containing from about 20% to about 50% by weight of an oil solution of oil-soluble alkali metal petroleum sulfonates with an amount of a water-soluble inorganic alkaline earth metal salt sufiicient to convert a substantial proportion of the alkali metal petroleum sulfonates to neutral alkaline earth metal petroleum sulfonates, and with sufficient water to cause the formation of a tertiary butyl alcohol phase containing an oil solution of neutral alkaline earth metal petroleum sulfonates dissolved therein, and

an aqueous phase; separating the phases thus formed;

References Cited in the file of this patent UNITED STATES PATENTS 2,361,476 I-Iigbee et a1. Oct. 31, 1944 2,402,325 Griesinger June 16, 1946 2,453,690 Bray Nov. 16,1948 2,689,221 1954 Bray Sept. 14, 

1. THE METHOD OF PREPARING AN OIL SOLUTION OF OILSOLUBLE BASIC CALCIUM PETROLEUM SULFONATES WHICH COMPRISES CONTINUOUSLY CONTACTING A TERTIARY BUTYL ALCOHOL SOLUTION CONTAINING FROM ABOUT 30% TO ABOUT 40% BY WEIGHT OF AN OIL SOLUTION OF OIL-SOLUBLE SODIUM PETROLEUM SULFONATES WITH AN AQUEOUS SOLUTION CONTAINING FROM ABOUT 20% TO ABOUT 30% BY WEIGHT OF CALCIUM CHLORIDE AND CONTAINING FROM ABOUT 1.5 TO ABOUT 2 MOLAR EQUIVALENTS OF CALCIUM CHLORIDE PER EQUIVALENT OF SODIUM SULFONATE, WHEREBY A TERTIARY BUTYL ALCOHOL PHASE CONTAINING AN OIL SOLUTION OF OIL-SOLUBLE NEUTRAL CALCIUM PETROLEUM SULFONATES, AND AN AQUEOUS PHASE ARE FORMED; CONTINUOUSLY SEPARATING THE ALCOHOL PHASE FROM THE AQUEOUS PHASE; CONTINUOUSLY ADDING TO SAID ALCOHOL PHASE FROM ABOUT 0.75 TO ABOUT 1.5 MOLAR EQUIVALENTS OF CALCIUM HYDROXIDE PER EQUIVALENT OF SODIUM SULFONATE, AND A SUBSTANTIAL AMOUNT OF WATER, THE AMOUNT OF SUCH ADDED WATER BEING SUCH THAT WHEN THE ALCOHOL IS REMOVED FROM THE MIXTURE AS IS HEREINAFTER PROVIDED, THE RESULTING MIXTURE CONTAINS FROM ABOUT 4 TO ABOUT 8 PER CENT BY WEIGHT OF WATER; CONTINUOUSLY REMOVING SAID ALCOHOL FROM THE RESULTING MIXTURE, AND THEREAFTER CONTINUOUSLY REMOVING THE REMAINING WATER FROM THE ALCOHOL-FREE MIXTURE, WHEREBY AN OIL SOLUTION OF OIL-SOLUBLE BASIC CALCIUM PETROLEUM SULFONATES IS OBTAINED. 